Fluid operated switch



June 9 H. VAN 'VALKENBURG ET AL 1,962,221

TCH

FLU ID OPERATED SWI Filed Jan. 25, 1932 2 Sheets-Sheet l mentors //://Z///y i/ar/ r? J mmaa/ m J Gttoreg M M m June 1934- H. L. VAN VALKENBURG ET AL 1,962,221

FLUID OPERATED SWITCH Filed Jan. 25, 1952 2 Sheets-Sheet 2 m (Ittorneg Patented June 12, 1934 UNITED STATES,

1 1,962,221 \FLUID orfifim'rnn swrrcn Hermon L. Van Valkenburg, Wauwatosa, and Ward H. Spencer, Milwaukee, Wis., assiznors to Square D Company, Detroit, Mich.

Application January 25, 1932, Serial No. 588,738

a 2 Claims. (01. zoo-s4) This invention relates to fluid operated switches and is particularly directed to a switch operated by a float or other member located within a tank and responsive to the fluidcondition 5 therein, such as the fluid height, and operating an electric switch located externally of the tank.

Objects of this invention are to provide a float operated electric switch which is so constructed that the float is actuated from the liquid within a tank, which maybe a closed tank, and subjected to a difierence in pressure from that existing on the outside .of the tank, and in which the electric switch is located externally of the tank and is thus adequately protected from any damage from the liquid within the tank, and which is also externally accessible for adjustment, inspection or repair, thus, on the one hand providing a construction in which'danger from damage to the switch is wholly avoided, and, on the other hand, providing the utmost accessibility.

Further objects are to provide a float operated switch which is so constructed that the mechanism within the tank responsive to fluid condition therein operates the mechanism of the switch 10- cated externally of the tank, and yet a fluid seal or gas seal is provided at that point in the construction where the connecting mechanism passes from the interior to the exterior of the tank, and to so organize the construction that the effect of pressure within the tank will neither augment or detract from the effect of the float or other mechanism, or in other words, which will permit the free operation of the switch located externally of the tank by means of the float or other member located internally of the tank without imposing an uncertain loss or frictional loss on the mechanism and without imposing any load tending to resist or assist themotion of the mechanismbut which is substantially inert in its 49 efiect-on the mechanism.

It has been found that with flexible sealing means connected to moving partsonjone side. of whichthere is pressure and on the other side of which there is adifierence in pressure, that the flexible means tends to assume and maintain a certain shape due to the fact that its displacement is greateror 'lessidepefiding"ofi'th' differ-" ence in pressure in one position'thanin another position, so that there is a resistance to change in one direction and an unwanted addition or assistance to a change in the other direction; In other words, if the tank to which the apparatus is applied has a pressure greater than that of the external air, it has been found that if the flexible mechanism and its associated-partscare so constructed, that a displacement or decrease in volume occurs in one direction of travel, that travel in this direction will be assisted due to the pressure in the tank, and that travel in the other direction will be resisted due to the pressure in to the tank,. inasmuch as there is a difference in displacement in the two positions that the parts may occupy.

This invention employs this principle which has been discovered in connection with this mechanism, and this invention provides an apparatus which is so made that the displacemem from one extreme position of the mechanism to the other extreme position of the mechanism is substantially constant and consequently the dif- 7o ference in pressure within and without the tank does not affect the smooth, uniform and accurate operation of the'apparatus.

Further objects of this invention are to provide a flexible sealing means and a mechanism associated therewith for a float operated electric switch which is so made that the diiierence in pressure within and without the tank is borne by means which relieve the operating mechanism from any strain or forces tending to affect the so free and accurate operation thereof.

In greater detail, further objects, of this invention are to provide a float operated electric switch which is so constructed that the float is located within the tank and the switch externally 55 of the tank, and a flexible mechanism, such as a metal bellows, commonly known as a sylphon, may be employed, the collapsing or expanding action of the sylphon due to the difl'erence in pressure externally and internally of the tank being resisted by a rigid pivotal support for a member carried by the sylphon itself and located at-such a point within the sylphon or metal bellows that there is substantially no change in volume due to the different positions into which the apparatus isrocked when the mechanism operates, and to so construct the mechanism that there are no stresses imposed on the operating mechanism, the intermediate mechanism or the switch mechanism due to the difference in pres- 1 sure within and without the tank, ,Further objects are to provide a construction in which the flexible-sealing means has very little motion at any one point, that is to say, i which 05 the movementof the parts of the flexible sealing means is not localized but is distributed over a relatively great area, and in which the means resisting collapsing or expanding'otthe flexible mechanism also'constitutes a portion of the intermediate mechanism joining the internally located float and the externally located electric switch.

Further objects are to provide a construction in which a float operated electric switch is pro vided for use on a closed tank in which a mounting and sealing flange or fitting is furnished, functioning both to close the opening in the tank and also to mount and hold both the externally located switch and the internally located float mechanism within position so that the entire device may be removed or replaced as a unit.

Further objects are to provide a float operated electric switch which is applicable to the control of a liquid level within a tank having a diiference in pressure within and without the tank, in which an externally mounted switch is operable from the float, and in which the leverage, lost motion, throw, or other characteristics of the switch are externally adjustable without opening or breaking the flexible seal through which the mechanism operates.

Further objects are to provide a construction having the above detailed and hereinafter outlined desirable characteristics, which is of simple construction, which is sturdy and rugged, and which is easy to adjust and instal.

Embodiments of the invention are shown in the accompanying drawings, in which:

Figure 1 is a side elevation of the apparatus with a portion of the tank shown in section.

Figure 2 is asectional view on the line 2-2 of Figure 1.

Figure 3 is an enlarged sectional view on theline 3-3 of Figure 1.

Figure 4 is a sectional view on the line 4-4 oi? Figure 3, showing the mechanism in one extreme position.

Figure 5 is a view corresponding to Figure 4 growing the mechanism in another extreme posi- Figure 6 is a fragmentary view showing a slightly diflerent form of the invention.

Referring to the drawings, particularly Figures 1 to 5, it will be seen that the tank 1 is provided with an aperture 2 through which the mechanism is inserted. This aperture is closed by means 01' a cap or fitting 3 secured thereto by screws or other means 4, and preferably provided with a sealing gasket 5, as shown in Figure 1. As

shown in greater detail in Figures 3, 4 and 5, the' cap or aperture cover 3 is provided with an aperture 6 approximately centrally thereof. A metal bellows, commonly known as a sylphon, or other flexible sealing means, '1 has one end secured at the aperture 6. Preferably ii! a sylphon is used, as shown in the drawings, a flange 8 is formed thereon and soldered or otherwise secured to the inner wall oi the aperture 6, see Figure 3. The other end of the sylphon is reinforced and closed by means of a metal disc 9 soldered or otherwise secured thereto. This disc rigidly carries a lever or connecting or operating member 10 which, as stated, is rigid with the disc 9 and consequently rigidly joined to the inner portion of the sylphon.

To prevent the diiierence in pressure within and without the tank from either collapsing or expanding the sylphon, a rigid supporting member pivotally carries the lever 10. In the form shown,

a pair of inwardly projecting ears 11 are rigidly mounted upon the cap or cover member 3 and project into the open central portion of the metal bellows or flexible members 7.

The lever 10 freely passes between the ears or supporting arms 10 and is mounted upon a pivot pin 12 carried by said arms 11, as shown in Figures 3, 4 and 5.

At this point it is to be particularly noted that the pivot pinis so located axially or the metal bellows or flexible sealing member that the flexible bellows 7 has substantially the same volumetric displacement in all positions. An attempt to roughly indicate that has been made in Figures 4 and 5. The sylphon when displaced by the rocking of the lever 10, expands on one side and contracts on the other so that from actual experiments and tests conducted with this apparatus, it has been found that the displacement is substantially constant throughout the entire range of action of the apparatus. Consequently, inasmuch as the volumetric displacement is substantially constant, there is no force either assisting or resisting free pivotal or rocking action of the lever 10, although this lever is sealed by means 01 the flexible sealing member so that it passes from the interior to the exterior of the tank.

Referring in greater detail to Figures 3, 4 and 5, it will be seen that the inner end of the lever 10 is forked or slotted, as indicated at 13 in Figures 4 and 5, and that this slotted end receives the transverse pin 14 carried by the short lever arm of the fitting 15 for the float rod 16, the float being indicated at 17 in Figure 1. The arm 16, fitting 15 and the pin 14 thus constitute the float lever which is pivoted upon a pin 18 carried by inwardly projecting rigid arms 19 forming an internal frame work rigidly secured to the cap.

Externally an electric switch, indicated generally at 21, is mounted upon outwardly projecting bracket arms or supports 22, see Figure 1, and these supports are provided with down turned portions 23 rigidly mounted upon the cap or cover 3. It is preferable to utilize the same rivets indicated at 24 in Figures 2, 3, 4 and 5 to secure the internal arms or supports 19 and the external arms or supports 22, as indicated in the drawings, although this feature, Q2 course, is more a matter of economical design, although it has been found to aid in the rigidity and simplicity of the structure.

The supporting arms 11 which carry the lever 10 are provided with outwardly turned feet 25, see Figure 2, which are riveted or otherwise secured to the cover or closure disc 3.

There is no chance whatsoever of the liquid within the tank damaging the electric switch, as the construction is such that the electric switch is mounted externally of the pressure tank, although the float mechanism is mounted internally of the pressure tank.

It is to be noted further that means are provided for adjusting the leverage between the float and the switch, and that such adjustment may be made externally of the tank. As shown in Figure 1, the electric switch is provided with an operating lever 26 provided with a plurality of spaced apertures 27, and that the intermediate tween the float and the switch and permitting this variation or adjustment of the leverage ex-= ternally of the tank; even after the apparatus is installed, if desired.

Further, the length of the link may be varied. as one of the members thereof carries a threaded extension or stem 30 screwed into the other portion of the lever and locked by a lock nut, as shown in Figure 1.

It is sometimes desirable to provide for lost motion in these mechanisms and this is readily obtained by the construction shown in Figure 6. For instance, the switch lever 26' is provided with a right angle extension 31 equipped with a plurality of apertures 32, through any one of which the stem 34 of the connecting link may pass. This connecting link is provided with a lower collar 35 and an upper collar 36, either or both of which may be adjustable on the stem 34.

In the construction chosen for illustration in Figure 6, a portion at least of the stem is threaded and the member 36 screwed thereon, so that it may be raised or lowered, a lock nut being provided for locking the member 36 in place as indicated. The lower end of the stem is threaded and is screwed into the yoke or lower pivot portion 37, of the link, and locked by means of a lock nut 38 so that either or both the upper or lower member may be adjusted with relation to the operating lever 31 of the switch.

It will be seen that a float operated switch has been provided which may be used with a closed tank even when there is a diiference in pressure internally and externally of the tank without any interference, due to this pressure, to the free and accurate functioning of the mechanism.

It will be seen further that the device is re movable or replaceable as a unit, as the cap 3 may be removed and will carry the entire mechanism therewith, the float 17 freely passing through the aperture 2 in the tank, as is apparent in Figure 1.

Further it will be seen that there is no chance of damaging the switch due to the liquid within the tank, as the switch is located'wholly externally of the tank.

Also it is to be noted particularly that the leverage, adjustment, and lost motion may be varied, as desired, externally of the tank even after the apparatus is installed' It will be seen further that all of these highly desirable results are obtained through the medium of a very simple and practical structure which under actual tests has been found to function in a highly satisfactory and practical manner.

Although this invention has been described in considerable detail, it is to be understood that such description is intended as illustrative rather than limiting, as the invention may be variously embodied and is to be interpreted as claimed.

We claim:

1. A liquid receiving tank having an opening therein, a plate closing said opening, said plate having an opening therethrough, a metal bellows having an open end whose margins are sealed to said plate and surround the opening in the plate, said bellows having a closed end projecting into said tank, a pair of fulcrum members carried by said plate and projecting into said bellows, a lever pivotally mounted upon said fulcrum members at a non-shifting point within said bellows intermediate the ends of the bellows and projecting outwardly beyond said plate and inwardly beyond the closed end of said bellows and sealed to the closed end of said bellows, float mechanism of smaller diameter than the opening through said tank and operatively connected to the inner end of said lever and supported from said plate, and an electric switch supported by said plate on the outer side of said plate and operatively connected to the outer portion of said lever.

2. A liquid receiving tank having an opening therein, a plate closing said opening, said plate having an opening therethrough, a metal bellows having an open end whose margins are sealed to said plate and surround the opening in the plate, said bellows having a closed end projecting into said tankfa pair of fulcrum members carried by said plate and projecting into said bellows, a lever pivotally mounted upon said fulcrum members at a non-shifting point within said bellows intermediate the ends of the bellows and projecting outwardly beyond said plate and inwardly beyond the closed end of said bellows and sealed to the closed end of said bellows, float mechanism of smaller diameter than the opening through said tank and operatively connected to the inner end of said lever and supported from said plate, and an electric switch supported by said plate on the outer side of said plate and operatively connected to the outer portion of said lever, said plate having a second pair of fulcrum members supported from the inner side of said plate and located on opposite sides of said bellows and pivotally supporting said float means, said bellows being deformable when said lever rocks and maintaining substantially constant volumetric displacement in the different positions caused by the rocking of. said lever.

HERMON L. VAN VALKENBURG. WARD H. SPENCER. 

